The General Motors 3800 engine is a 3.8-liter V-6. This engine is installed across a variety of GM vehicles, though is primarily found in the Pontiac and Buick vehicle lines. The 3800 engine's fuel injectors operate in conjunction with a pressurized fuel system. At the top and bottom of each injector, an o-ring acts as a seal to ensure fuel does not leak. Damaged or degraded o-rings may cause fuel leaks and fire hazards. O-ring replacement is recommended if they are leaking or any time the injector is removed from the fuel rail or engine.
Remove the electronic plug from the fuel safety cut-off switch to turn off the fuel pump. The cut-off switch location can be found in your vehicle's owner's manual.
Depressurize the fuel system by attempting to start the car three times, for 3 to 5 seconds each time. Allow a 10-second pause between attempts to allow the starter to cool. Without re-pressurization from the fuel pump, the existing pressure in the fuel lines will be reduced due to fuel consumption by the engine.
Disconnect the negative battery terminal.
Locate the fuel rails and remove any engine shrouds, intake tubes, vacuum lines or bolt-on accessories to allow access. Unbolt the fuel rail from the engine if your vehicle's rails are secured.
Disconnect the fuel injector electronics plug. Disconnect the fuel rails by pulling upward and away from the top of the fuel injector. Some fuel will spill. Allow it to evaporate, or wipe it away, before continuing.
Pull upward on the fuel injector to remove from the engine. The fuel injector may need to be rocked slightly to allow the bottom o-ring to disengage.
Remove the o-rings from the injectors by sliding them off the top and bottom of the injector.
Wipe away any dirt or debris from the injector o-ring seal point.
Lubricate the new o-ring with a light coating of motor oil. The motor oil will not only make it easier to slide on, it will protect the o-ring once installed. Apply a small amount of motor oil to your finger and wipe over the entire surface of each o-ring.
Slide the o-rings onto the fuel injector.
Push the injector into the engine hole until the o-ring is fully seated. A properly seated injector will resist removal.
Push the fuel rail or fuel line directly down on top of the fuel injector. Misaligned pressure may cause small tears in the injector creating future leak points. Connect all fuel injectors.
Replace the electronics plug on each fuel injector. Secure the fuel rail to the engine, if required. Attach any bolt-on accessories, vacuum hoses, and intake tubes. Reconnect the fuel safety shut-off switch electronics plug. Reconnect the car battery.
Turn the ignition switch to the electronics mode. Allow the fuel pump to pressurize the fuel system. With the ignition switch in the electronics mode, the pressurization should take 3 to 5 seconds. Turn off the key and repeat this step twice.
Inspect the fuel system for leaks. Return to Section 1, if necessary. Replace the engine shroud. Start the vehicle to confirm installation.
